             (:del) ;; maybe we need a special category for :del ?
             (Alhs [:assigned] x E)
             (:import :from)
-            (w (NIY))
+            [x E] ;; untouched in this pass
             (:assign-expr)
             (let [[ls r] t
                   [rhs E] (A r E)

       (:star)
       (rec)
       (:subscript) ;; not pure
       (let [[o ss] x
             [o E] (Alhs o E)]
         (A* (list h o) ss E))
       (:select) ;; not pure
       (let [[o n] x
             [o E] (Alhs o E)]
         [(list h o n) E])
       (:argument) ;; for use in def
       ($syntax-error)))
   :else ($syntax-error)))


                  [clauses E] (thread-args
                               () (fn [[expr target] E]
                                    (let [[expr E] (A expr E)
                                          [target E] (Alhs [:assigned] target E)]
                                      [[expr target] E])) clauses E)
                  [body E] (A body E)]
              (w [(list h clauses body) E]))
